I am a 29 year old male who is very active. I lift weights Mon-Wed-Fri and do 20 minutes of high intensity circuit running Tues-Thur-Sat.
About 10 weeks ago I woke with a strange feeling that my heart was racing. Not sure what to do, I called 911. I went to emergency and the EKG was normal and blood test showed that no heart damage enzymes were released. My AST and ALT were a little high. Over the next few days I was uncomfortably aware of my heart beat but that went away. Over the next six weeks I carried on with my exercise routine and diet as normal and I didn't experience any pain.
About 4 weeks ago I woke up in the middle of the night again with the same feeling. I convinced myself that it was all in my head and went back to bed. Again I was uncomfortably aware of my heart beat for a few days. After a couple of days I started to feel a little pain in my chest. I would describe it as a slight, tight and pinching feeling in the center.
I went to see my PCP who said given my age and the normal EKG from the ER, I should be fine. I asked to see a cardiologist just for peace of mind.
The cardiologist gave me an EKG and checked my pulse over the entire body and did some listening and he said everything was normal. He suggested I put on a 24 hour monitor. I scheduled the appointment for a week and a half later as I had to go out of town.
Since the chest pains have started I know that anxiety has become an issue. I don't know if it was the initial problem but it is one now as every time I feel a pain I think negative and I can feel an adrenaline release that makes it worse.
While I was out of town (over the last week and a half) the chest pains have been growing steadily worse. In the beginning I would define them as a level 1 pain and now I would say they are level 3. I am experiencing shortness of breathe and the pain lasts all day. When I wake up in the morning I feel fine but after an hour or two it starts and lasts until I go to bed. After I returned home I did go into the emergency room again and the EKG and blood tests were normal again. I did the 24 hour monitor but won't receive the results until this coming Wednesday.
Three nights ago I was feeling the pain fairly intense and I was afraid it was my heart again. I decided to go for a run. My thinking was, if this is my heart we'll just find out. Maybe that was foolish but I did my regular run and pushed almost as hard as normal and immediately after I actually felt better. There was almost no pain. Last night I did the same thing. The pain didn't go away as well but it was less intense after the run.
I know that anxiety is an issue here since I get nervous because of the pain but I really don't believe anxiety can be the cause. I am generally happy in life and not too stressed. Besides, the pain is almost a constant tightness. Sometimes I feel it on the left and sometimes on the right. Mostly right in the center. A lot of times it is a slight burning sensation just under my sternum. I also feel it up in my lower neck from time to time. If that wasn't enough there are "popping", "shooting", and "stabbing" sensations. The popping and shooting feeling unnerve me but the stabbing hurts. Yesterday I was having an irregular beating feeling in my upper abdomen. I think that is about it.
I really appreciate your time in considering these matters. I believe I could rest easier if I just knew what this is. Is it possible with several normal EKGs and the running that I have done that this could be my heart? If not the heart, then what could cause these pains? Thanks for your time.

I had an ultrasound done that was all normal. No stones.
I have been taking 40mg of Prilosec OTC since Tuesday the 17th. If my probelm is reflux should that have stopped it already?
I don't have nausea but I have a feeling like I need to vomit or burp that is ubiquitous with the chest pain.

On clinical grounds you do not seem to have cardiac pain. However it is advisable to undergo a Stress EKG as well as a Color Doppler Echocardiogram. Likely diagnosis would be a Mtral Valve Prolapse syndrome, a benign condition where one of the heart valves is a little long and it "skids" while closing under force. This is not considered actually a disease and is a normal variation.

Second possibility is aGastroesophgeal reflux. This is a form of Acidity disorder where acid from the stomach rushes back in the foodpipe and mimicks the heart pain.